According to femalefirst.co.uk Zac Efron's foot got stuck in a theatre seat while filming High School Musical 3.
“I don’t know how it happened but my foot slipped through a theatre seat during filming and I couldn’t get it out. It was so funny because they had to take the seat apart to rescue my foot. The cameras had to stop rolling and people were brought on set to unscrew the bottom of the chair. I was mortified,” Zac said.